To test the value of preoperatively performed urodynamics with regard to outcome of surgery for stress urinary incontinence (SUI) and to examine whether it is costeffective not to perform urodynamics preoperatively using the non-inferiority assumption.

Study design:

Multicentre, randomized controlled multidisciplinary trial.

Study population:

Women with symptomatic stress urinary incontinence in whom conservative measures failed and in whom surgical treatment is considered. Only those women in whom the urodynamic findings are discordant with the findings based on history, clinical examination and 48h voiding diary will be randomized.

Intervention:

Surgical therapy versus any other therapy (surgical therapy or conservative treatments) as based on individual findings.

Outcome measures:

Primary outcome: Non inferiority of the improvement of the UDI one year after treatment.

Secondary outcomes: Cure of incontinence as measured with voiding diary. Complications of surgery for stress incontinence in particular re-operation and overactive bladder symptoms of quality of life as measured by validated questionnaires.

Power / data analysis:

600 women will be included in the study, of whom 200 women will have discordant findings between history and urodynamics. Anticipating a 50% participation rate of women with discordant findings will be randomized to each group (51 per group). As based on the non-inferiority assumption, the mean improvement in UDI in both groups is expected to be 35 with standard deviation 10. A difference in mean improvement of 5 or less is considered non-inferior (power 80% using one-sided testing at 0.05).

Economic evaluation:

For each patient, utilization of health care services will be recorded prospectively, using Case Record Forms, including urodynamic testing, surgery for SUI, re-operations, medical treatment for detrusor instability, care for urinary incontinence, and care for urinary retention.